Welcome to the airlines section! Tip #5 is knowing airliners fleet. This can drastically improve your chances of identifying the aircraft. For example, Ryanair only operate Boeing 737's. So, if you ever see a Ryanair aircraft, you know it's a 737!
Choose from a number of airlines in the menu on the left to learn more about them. Learn about their history if you desire and remember their fleet. Some are easier to remember than others so it will take time to remember. Practice makes perfect!